1. Field of the Invention
The present invention relates generally to shading mechanisms used to control the passage of sunlight into a space to be illuminated, and more particularly, to a venetian blind structure incorporating light-transmissive prismatic slatted panels for reflecting glaring direct rays of sunlight while transmitting indirect rays of sunlight.
2. Description of the Prior Art
Many types of curtains, blinds and screens are known for controlling the amount of natural daylight admitted into a room or building through a window, skylight, or other light opening. In most cases, such curtains, blinds or screens are totally or partially opaque to shade the area to be illuminated from direct glaring rays of sunlight. However, the opaque portions of such light control devices also block indirect rays of sunlight which strike such opaque portions from reaching the area to be illuminated. In addition, such opaque light control devices absorb heat from blocked rays of direct sunlight, and may thereby add undesired heat to the area being illuminated.
Light control mechanisms have also been disclosed wherein transparent lenses, slats, or blinds are used to selectively admit or reflect rays of sunlight. For example, U.S. Pat. No. 3,438,699 discloses a multiple slat assembly similar to a venetian blind wherein each slat is composed of two transparent pieces of material having interfitting prisms to exclude light and heat rays coming from a particular direction. U.S. Pat. Nos. 2,812,690; 2,812,691; 2,858,734; and 2,993,409 all disclose skylights having prismatic lenses for selectively admitting or reflecting rays of sunlight. U.S. Pat. No. 2,812,692 discloses a glass block structure using prismatic surfaces to selectively admit or reflect rays of sunlight depending upon their angle of entry. U.S. Pat. No. 3,393,034 discloses a light control blind using a series of elongated rectangular panels, each panel being formed of intermeshing pairs of prismatic plates for blocking downwardly directed light rays while permitting the passage of upwardly directed light rays. U.S. Pat. No. 4,517,960 also discloses a slatted structure wherein light-permeable slats have a prismatic surface for reflecting direct overhead rays of sun.
Apart from blocking direct rays of sunlight from passing into the illuminated space, it is also an objective of many light control blinds to permit a person within the illuminated area to be able to look through the blind in order to view the outdoors. Some prior art devices achieve this objective by intermeshing a second prismatic panel with the first prismatic panel, so that light rays refracted away from their original angular path by the first prismatic panel are refracted back to their original angular path by the second prismatic panel. However, such structures often exhibit alternating clear and dark bands which are distracting and which interfere with a clear view through the blind structure. Moreover, the blind structures shown in U.S. Pat. Nos. 3,438,699 and 4,517,960 use linear prisms which are formed symmetrically about the light entry face of each slat; accordingly, the slats of each such blind structure would need to be set at approximately a 45.degree. angle in order to ideally reflect direct rays of sunlight approaching from a 45.degree. angle of elevation from the horizon. However, positioning the slats at a 45.degree. angle would virtually eliminate any level line of sight between adjacent slats. Furthermore, while such prior art blind structures may permit limited viewing of the outdoors through the slat elements themselves, any attempt to incorporate a diffusion element to more evenly diffuse the light transmitted by such slats would interfere with the ability to view the outdoors through the slats of the blind.
Accordingly, it is an object of the present invention to provide a shade mechanism which permits the passage of indirect rays of sunlight into a space to be illuminated while substantially reflecting direct rays of sunlight away from the space to be illuminated.
It is another object of the present invention to provide such a shade mechanism which minimizes any interference with vision through the shade mechanism for a person located within the illuminated space attempting to view the outdoors.
It is still another object of the present invention to provide such a shade mechanism using a plurality of transparent, prismatic slatted panels adapted to reflect direct rays of sunlight, which slatted panels are normally oriented in a position which permits level vision between adjacent slatted panels.
It is yet another object of the present invention to provide such a shade mechanism wherein light transmitted through such slatted panels may be diffused to more evenly illuminate the illuminated space without interfering with vision through the shade mechanism.
It is a further object of the present invention to provide such a shade mechanism which minimizes heat gain from direct rays of sunlight.
It is a still further object of the present invention to provide such a shade mechanism which may be used on vertical light openings, such as conventional windows, as well as in conjunction with horizontal or slanted light openings.
These and other objects of the present invention will become more apparent to those skilled in the art as the description thereof proceeds.